Blog Archives

Follow Up on Spatial Overlays with R – Getting Altitude for a Set of Points

September 16, 2013
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Follow Up on Spatial Overlays with R – Getting Altitude for a Set of Points

A short follow up on a previous post on spatial overlays with R. library(sp)library(dismo)# some addresses in Austriapts # make pts spatialcoords spdf_pts # assign CRS/projection (which is WGS 1984)crs proj4string(spdf_pts) # spatial data to extract (altitude)alt # convert alt from raster to grid (needed for over::sp)# and assign CRS (which is the same...

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Loading Multiple Shapefiles to the R-Console Simultaneously

September 10, 2013
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A quick tip on how to load multiple shapefiles (point shapefiles, i.e.) to the R console in one go:library(sp)# get all files with the .shp extension from working directory setwd("D:/GIS_DataBase/GIS_Tirol/Tirol_Verbreitungskarten/Verbreitungs_Daten")shps # the assign function will take the string representing shp and turn it into a variable# which holds the spatial points datafor (shp in shps) assign(shp, readShapePoints(shp))# ...done

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Text Mining with R – Comparing Word Counts in two Text Documents

August 19, 2013
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Here's what I came up with to compare word counts in two pieces of text. If you got any idea, I'd love to learn about alternatives!## a function that compares word counts in two textswordcount ...

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Spatial Overlays with R – Retrieving Polygon Attributes for a Set of Points

June 19, 2013
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A short tutorial for spatial overlays using R-GIS..library(sp)library(dismo)# spatial dataalt gadm # viewplot(alt)plot(gadm, add=T)# some addressespts # make it spatialcoords spdf_pts # assign CRS/projectionproj4string(spdf_pts) # check datastr(spdf_pts)# plot it on topplot(spdf_pts, cex = 2, col = 2, add = T)# do an intersection (points in polygon)# yielding the polygon's attribute dataover(spdf_pts, gadm)

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R GIS: Terrain Analysis for Polygons as Simple as it Gets!

June 18, 2013
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R GIS: Terrain Analysis for Polygons as Simple as it Gets!

library(rgdal)library(raster)alt gadm gadm_sub plot(alt)plot(gadm_sub, add=T)asp slo > extract(slo, gadm_sub, fun = mean, na.rm = T, small = T, df = T) ID slope1 1 9.9590532 2 1.0474433 3 7.4561654 4 1.6737865 5 11.946553> extract(asp, gadm_sub, fun = mean, na.rm = T, small...

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Use R to Bulk-Download Digital Elevation Data with 1" Resolution

June 18, 2013
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Here's a little r-script to convenientely download high quality digital elevation data, i.e. for the Alps, from HERE:require(XML)dir.create("D:/GIS_DataBase/DEM/")setwd("D:/GIS_DataBase/DEM/")doc urls names for (i in 1:length(urls)) download.file(urls, names) # unzip all files in dir and delete them afterwardssapply(list.files(pattern = "*.zip"), unzip)unlink(list.files(pattern = "*.zip"))p.s.: Also check raster::getData which pulls SRTM data at 90m resolution for a location / region!

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R Quick Tip: Shutdown Windows after Script Has Finished

May 21, 2013
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Quite often I have long procedures running and want to do this over night. However, my computer would still be running all night after the script has finished. This is easily circumvented by the following lines that I put at the end of such a script:# set working dir# setwd("C:/Users/Kay/Desktop")# long procedure:for(i in 1:1e+5) {cat(i); cat("\n..................\n")}d # save...

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Creating a QGIS-Style (qml-file) with an R-Script

May 6, 2013
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Creating a QGIS-Style (qml-file) with an R-Script

How to get from a txt-file with short names and labels to a QGIS-Style (qml-file)? I used the below R-script to create a style for this legend table where I copy-pasted the parts I needed to a txt-file, like for the WRB-FULL (WRB-FULL: Full soil code o...

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Programmatically Download CORINE Land Cover Seamless Vector Data with R

April 21, 2013
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Programmatically Download CORINE Land Cover Seamless Vector Data with R

Thanks to a helpful SO-Answer I was able to download all CLC vector data (43 zip-files) programmatically:require(XML)path_to_files dir.create(path_to_files)setwd(path_to_files)doc urls # function to get zip file namesget_zip_name # function to plug into sapplydl_urls # download all zip-filessapply(urls, dl_urls)# function for unzippingtry_unzip # unzip all files in dir and delete them afterwardssapply(list.files(pattern = "*.zip"),...

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Download File from Google Drive/Docs Programmatically with R

April 11, 2013
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Following up my lattest posting on how to download files from the cloud with R..dl_from_GoogleD ## Arguments:## output = output file name## key = Google document key## format = output format (pdf, rtf, doc, txt..)## Note: File must be shareable! ...

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